Like any living organism the plants are subjected to numerous environmental, both abiotic and biotic, stresses. Drought, soil salinity, alkalinity and extreme temperatures are included among the abiotic stresses. Among the biotic stresses are included pests as insects, arachnids and nematodes, and pathogens such as bacteria, viruses and fungi. All these biotic and abiotic factors, manmade and natural are working together to make the global farming situation a lot more difficult than it has ever been. Unfortunately the conventional approach to problem solving has not yielded the desired results. As a result of this, we are facing a situation where the world population is increasing by 1.7% pa and food production is stagnating for the last 6 years.
Plants are subject to a wide variety of fungal, viral and bacterial diseases and damage by insects. Fruit bearing plants, in particular citrus trees are subject several totally destructive diseases like root rot and gummosis caused by Phytophthora citrophthora and Huanglongbing/Citrus Greening (Liberibacter asiaticus (CGD), which is vectored by the Asian citrus psyllid (ACP), Diaphorina citri Kuwayama. 
Citrus gummosis and Huanglongbing are particular problems for citrus crops as is the insect vector, Citrus Psyllid. Presently, Huanglongbing is prevalent worldwide throughout all the countries that produce citrus; there is no known or reported cure. The official, sometimes mandated, scientific worldwide recommendation is for trees identified as affected with Hunaglongbing to be removed and burned. In the case of Phytophthora, hundreds of thousands of acres of various crops worldwide have been destroyed because of the effects of this pathogen, which has been historically known to have caused mass human migration due to famine. Presently the only official recommendation by the scientific community is prophylactic by spraying chemical fungicides on the plant tissue of citrus trees, which has little or no effect because of the deep seated nature of the disease and the tendency of the pathogen to rapidly develop resistance and cross resistance to such fungicides. This results in growers being required to increase the dosage or frequency of application of the chemical fungicide with a devastating effect to the environment and raising costs of cultivation by as much as 40% as reported by studies conducted by the Universities of Florida and California.
Our studies reveal that the bacterial agent causing Huanglongbing has a symbiotic relationship with the Asian Citrus Psyllid, its main vector (as well as the African Citrus Psyllid—Trioza eritreae). The characteristic mottled yellowing of the foliage caused by this disease and the chemical signals released by the affected plant attract the insect in large numbers for feeding and egg laying. Upon ingestion of the bacteria infected plant sap, this insect flies off to healthier plants in the vicinity and rapidly infects healthy orchards. This insect has a reported flying radius of 1.5 kilometers and can therefore infect a large area. These pests are also carried by wind and storms over much larger distances and spread the disease to healthy areas so conventional methods of physical quarantine are eventually breached by this disease and no citrus growing region can be considered totally safe from this malaise.
These insects and their nymphs feed on young growing plant tissues and release toxins and possibly viruses causing these tissues to curl and deform and thereby stunting growth. Since it is the new tissues that ultimately yield the current season's crop, the combined effect of the diseases as well as the feeding activities of the insect can be devastating. Psyllids as well as their nymphs excrete a sweet fluid known as honey dew which covers the surface of the leaves. This attracts a fungus known as the sooty mould fungus (caused by several genera like Capnodium, Cladosporium, Aureobasidium, Antennariella, Scoria, Lirnacinula). This forms a black coating on the leaves preventing access to sunlight and thereby hampering photosynthesis. This reduces carbohydrate synthesis reducing availability of energy and weakens the diseased tree further. Another effect the HLB bacterium has on the infected psyllid is to increase its fecundity and egg laying. A single female psyllid is able to lay over 300 eggs and due to their early maturity, there can be as many as 4-5 generations of the insect developing in a single year with favourable climatic conditions, enough to cause an uncontrollable epidemic.
It would be desirable to have a cost effective alternative that would be eco friendly and can be applied to fruit bearing plants without causing a problem of excessive pesticides residues that can impact human health. A holistic system that can not only retard damage caused by fungal and bacterial diseases, insect vectors as well as the damage caused by their feeding while enabling farmers and growers to restore their orchards quickly to their prime health and yield potential.
While this pest can be and is controlled by several available chemical insecticides belonging to classes like organophosphorus, synthetic pyrethroids, neo nicotinoids and others, all these cause collateral damage to beneficial insects such as parasites and predators and are not amenable to eco friendly techniques like integrated pest management. They are also toxic to pollinators like honey bees and have been implicated in causing large scale death of this useful insect by causing Colony Collapse Disorder (CCD). This has resulted in restrictions on their use or the banning of many of these insecticides including neo nicotinoids by EU nations for certain applications in horticulture. It is necessary to point out that the indiscriminate use of chemical insecticides has resulted in the extinction or near extinction of honey bees in China and has seen the USA resorting to the unprecedented step of importing honeybees from Australia to tide over their shortage.
From what has been previously commented on the state of the art in the control of the psyllid vectors of the liberibacter bacteria which cause the HLB of the citrus, one reaches the conclusion that basically the control of HLB has conventionally relied on the use of insecticides. The biological alternative has been the use of the pyllid parasitic wasps, Tamarixia radiata and the Tamarixia dryi. Unfortunately, in Florida, neither the use of insecticides nor predators have prevented the establishment of HLB.
The danger for the soil, environment, plants, animals and people, that the excessive use of pesticides involves, has led the researchers to consider other strategies of protection of the crops. One of the possible strategies is the use of compositions that activate the natural defence mechanisms of the plants against the attacks of pathogens and pests, without implying the use of such compositions adverse effects on the soil, the environment, the plants themselves, animals or people. In this sense, we have been researching for 25 years, about the effect that the plant growth regulators could cause in the reinforcement of the natural defence mechanisms of the plants and, as a consequence, in the induction of resistance to pathogens and pests on the plants treated with said regulators. In these researches we have seen how certain type of plant growth regulators, the water soluble Vitamin K derivatives, was able to stimulate the natural defence mechanisms of the treated plants and as a result to induce resistance to the attacks of pathogens and pests. [“Compositions for inducing resistance to tracheomycosis in plants”. Patent: WO 95/03702, published: 9 Feb. 1995]; [“use to compositions containing menadione for biostimulation of the plant mechanism in order to induce its resistance to pathogens and pests]. Patent: [95 ES-9500522, published: 16 Apr. 1999]
Another prior art WO96/28026 discloses application of compositions which contain as active components vitamin K3 and/or at least one of their water-soluble derivatives, preferably menadione sodium bisulfite (MSB), and/or at least one of their derivatives having a low water solubility, preferably menadione nicotinamide bisulfite (MNB), and are in the form of an aquous solution intended to biostimulate the metabolism of plants in order to induce their resistance to pathogens and pests and/or advance the blooming of plants. In a preferred embodiment, the compositions are sprayed on banana trees.
Application of a wide range of antibiotics has also been attempted to control HLB, however these have not found favour for two reasons:                a) Many of the antibiotics have proved to be toxic to citrus        b) Due to their low residual action, multiple applications are required which raises costs        c) The most effective manner of application of antibiotics through stem injection is laborious, time consuming and expensive making it impractical for large scale use. Injuries to the stem of the citrus plant due to injections can predispose them to secondary infection by other fungal and bacterial pathogens.        
Secondary infections caused by the opportunistic infection by other soil dwelling pathogens and pests is quite common given the weakened state of the infested citrus crop. The mechanism of entry can be through root tips already damaged and killed by HLB. Inoculum of pathogens like Phytophthora exist in the soil in a weaker saprophytic state and also as their spores such as chlamydospores or zoo spores. These are activated when they come into contact with irrigation water and root hairs of the crop which release exudates and chemical signals that attract these pathogens.
Soil dwelling pathogenic nematodes (like Tylenchulus, Pratylenchus, Xiphinema, Belonolaimus, Meloidogyne, Radopholus and many others) also cause damage to the roots of citrus plants. If these are already weakened by HLB, their ability to meet the nutrient and water requirements of the tree is already seriously impaired. Secondary infestation by any soil pathogen or nematode can prove to be the tipping point that accelerates the death of the citrus tree.